Over the past several years, the Direct Carbon Fuel Cell has been under development for converting carbon directly to electricity. The Direct Carbon Fuel Cell is an electrochemical fuel cell that may be fueled with carbon. The cell comprises ash-free, turbostratic carbon particles derived from any source, including from pyrolysis of natural gas. However, none has proposed a means for directly decomposing natural gas within a Direct Carbon Fuel Cell while extracting hydrogen gas from the cell and leaving the carbon particles within the cell.
No Direct Carbon Fuel Cell to date has been directly fueled with natural gas (methane) or gaseous and liquid carbonaceous fuels. The invention described herein uses methane or natural gas as fuel in a direct carbon fuel cell to produce coproducts hydrogen and electricity. Additionally, calculations indicate that hydrogen can be sold for less than $1.00 per gallon of gasoline equivalent of hydrogen, much less than the current market price of gasoline; and electricity can be produced for about 6.5 cents per kilowatt-hour.
This invention is especially amenable to producing and supplying hydrogen at vehicle gas filling stations. A natural gas fed direct carbon fuel cell is much more efficient and economical than conventional steam reforming of natural gas now being deployed for supplying hydrogen at gas filling stations. It also can do so with considerably reduced greenhouse gas carbon dioxide emission compared with the conventional steam reforming process.
Carbon dioxide is emitted at 100% concentration, so it can be easily collected and either sold or sequestered. Furthermore, the present invention simultaneously produces electricity and hydrogen. The electricity can be sold to power companies and put back into the grid, or can be dispensed at the gas station for electrically powered vehicles, which some think will eventually overtake hydrogen-fueled vehicles. In any case, this system could independently supply hydrogen fueled vehicles and electrically driven vehicles.
Another decided advantage of this invention is that hydrogen and electricity are coproduced in one unit. This simplifies operations and considerably reduces capital investment that would otherwise be required using the known method involving steam reforming of natural gas.